The present invention relates to the relative positioning of components, the term xe2x80x9ccomponentxe2x80x9d being used herein in general terms to indicate any device.
The invention was developed by paying specific attention to the possible use for accurate positioning of electronic, optical and/or electro-optical devices and parts thereof.
In that area of application, optical alignment arrangements are frequently used which involve standard microscope lens arrangements. The corresponding processes are generally cumbersome and expensive to implement, while also requiring complex software tools. This applies particularly to methods based on pattern recognition techniques.
When optoelectronic devices such as lasers or photodiodes are to be positioned, methods may be resorted to involving reading and optimising photocurrents induced by optical signals in one or more of the components being positioned. This requires the optoelectronic device(s) to be displaced together with its/their electrical connections, which generally increases the complexity of any corresponding pick-up tool.
In U.S. Pat. No. 5,998,226, a system and a method are disclosed for determining the misalignment between openings located in the contact layer and the interconnect layer of a semiconductor component. Defective semiconductors can thus be readily identified. Specifically, a single multifunctional structure formed in the contact layer is used to determine the alignment accuracy of the contact layer and the interconnect layer by inline visual inspection and determination of the end of line electrical resistance properties of the semiconductor wafer. This solution still requires visual inspection with the ensuing disadvantages outlined in the foregoing.
The object of the present invention is to provide an arrangement for the accurate relative positioning of a first component and a second component wherein the intrinsic disadvantages of the prior art solutions considered in the foregoing are dispensed with.
According to the present invention, such an object is achieved by means of an arrangement having the features set forth in the claims which follows. The invention also relates to the method of using such an arrangement.
The solution of the invention exploits electrically conductive patterns, preferably at least partly provided in the form of metallic tracks located on opposed surfaces of the two components to be aligned.
The relative misalignment of the two components can thus be detected and evaluated by using simple and inexpensive electrical measurement tools. Accurate relative positioning of the two components in question can be achieved by means of an automated system adapted to produce small relative movements (xe2x80x9cmicromovementsxe2x80x9d) of the two components while monitoring the current flowing through the conductive tracks.
The electrically conductive tracks are provided in the form of conductive patterns xe2x80x9cwrittenxe2x80x9d e.g. by photolithographic processes on the opposed surfaces of the components to be positioned. The geometry of the patterns is chosen in such a way that electrical contacts are opened or closed depending on the mutual positioning of the two components.